Table 1.

Characteristics of patients in the untreated (cohort 1) and treated (cohort 2) cohorts

Untreated (cohort 1) set (n = 1,188)Treated (cohort 2) set (n = 2,334)
Age group≤40 (%)41–52 (%)53–64 (%)≥65 (%)Pa≤40 (%)41–52 (%)53–64 (%)≥65 (%)Pa
Total number (%)191 (16)477 (40)276 (23)244 (21)260683616775
Tumor size
 <2cm72 (38)215 (45)133 (48)124 (51)121 (46)327 (48)286 (47)328 (42)
 2–5cm190 (57)245 (51)139 (50)113 (46)112 (43)290 (43)261 (42)355 (46)
 > 5cm2 (1)4 (1)2 (1)2 (1)5 (2)9 (1)11 (2)9 (1)
 Unknown8 (4)13 (3)2 (1)5 (2)0.3222 (9)57 (8)58 (9)83 (11)0.517
Nodal status
 Negative160 (84)424 (89)263 (95)226 (93)74 (29)253 (37)261 (42)332 (43)
 Positive23 (12)41 (9)11 (4)8 (3)170 (65)376 (55)299 (49)357 (46)
 Unknown8 (4)12 (2)2 (1)10 (4)<0.000116 (6)54 (8)56 (9)86 (11)<0.0001
Histologic grade
 I14 (7)79 (17)35 (13)44 (18)24 (9)101 (15)81 (13)94 (12)
 II54 (29)163 (34)108 (39)113 (46)60 (23)213 (31)351 (41)325 (42)
 III109 (57)193 (40)102 (37)58 (24)143 (55)291 (43)216 (35)280 (36)
 Unknown14 (7)42 (9)31 (11)29 (12)<0.000133 (13)78 (11)68 (11)76 (10)<0.0001
ESR1 geneb
 Positive110 (58)340 (71.3)207 (75)189 (77.5)141 (54)376 (55)320 (52)433 (56)
 Negative81 (42)136 (28.5)69 (25)55 (25.5)117 (45)268 (39)194 (31)213 (27)
 Unknown0 (0)1 (<1)0 (0)0 (0)<0.00012 (1)39 (6)102 (17)129 (17)<0.0001
ErbB2 geneb
 Positive42 (22)107 (22)44 (16)27 (11)76 (29)159 (23)132 (21)142 (18)
 Negative149 (78)370 (78)232 (84)217 (89)0.001184 (71)524 (77)484 (79)633 (82)0.008
RFS
 Eligible patients, n1,150 (97%)1,751 (75%)
 Median follow-up9 y3.6 y
 Interquartile range6.6–11.4 y1–7 y
  • aP calculated using the χ2 test.

  • bESR1 and ERBB2 positivity and negativity was defined using gene expression (see Materials and Methods).